Plan: Visual tweaks for mission items

Plan: Survey and Corridor Scan now share same command sequence generation code

Survey And Corridor now share same transect generation code. Better unit tests for both with more coverage.

Force consistent setting for offline vehicle

Use only default values when running unit tests

Replaced not equal operator for double values to qFuzzyCompare

Set correct parameter type for signal

Added parent to the new FactMetaData objects to be owned by parent

Visual tweaks for mission items

Fixed suspicious if-expression

Stable_V4.0->master merge

Merge Stable to master. Fix up conflicts

Cherry pick from master

More changes to ArduPilot manifest lookup

Cherry pick from master

Fixed typo in TerrainAirMapQuery::_parseCarpetData

Start Mission: Better error message

Add EGL to gstreamer dependecies

Flight mode fix, cherry picked from master

Plan: Default for terrain display is visible

Add note about ADSB server settings

Backported fixes

Better error message

Plan: CONDITION_GATE command support

Add note about ADSB server settings